A communications network, such as a passive optical network (PON), transmits downstream communications signals from an optical line terminal (OLT) to an optical network terminal (ONT). The downstream communications signals include reference clock signal information. The ONT recovers the reference clock signal and transmits upstream communications signals to the OLT based on the recovered clock signal.
An OLT and/or an ONT can malfunction in such a way that its clock output signal has too high a jitter level. This malfunction can make it difficult for the receiver of that signal, either the ONT or OLT, to communicate. Excessive clock jitter may also result in intermittent communications errors which can be difficult to detect and compensate.